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Electronic Flora of South Australia Species Fact Sheet

Ptilocladia australis (Harvey) Wollaston 1968: 265, figs 5E–J, 12.

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Crouanieae

Selected citations: Huisman et al. 1990:


96. Kendrick et al. 1988: 204; 1990: 52. Silva et al. 1996: 422.

Crouania attenuata var. australis Harvey 1855a: 558; 1859b: 330.

Crouania australis (Harvey) J. Agardh 1876: 85. De Toni 1903: 1418. Guiler 1952: 97. Lucas 1909: 51; 1929a: 25. May 1965: 367. Sonder 1881: 12. Wilson 1892: 185. Womersley 1950: 179.

Thallus (Figs 20A, 22A) light to dark red-brown, 3–8 cm high, slender, much branched irregularly, branches terete, with whorls of whorl-branchlets (Fig. 22A) distinctly separated over most of thallus leaving the axial cells exposed between them, in lower parts covering most of the axes, lower branches 0.7–1 mm in diameter, tapering to 150–360 µm near apices. Attachment by rhizoids from axial cells and basal cells of whorl-branchlets; mainly epiphytic on Posidonia and larger algae. Structure. Axes with short apical cells, enlarging within a few cells to 10–15 µm in diameter and L/D 1–1.5, and increasing to 150–300 µm in diameter and L/D 3–5 in mid and lower parts, often short (L/D about 1) near the base; axial cells mostly remaining ecorticate, older axes with slight rhizoidal cortication; lateral branches arising from basal cells of whorl-branchlets. Whorl-branchlets in whorls of 4, 120–270 µm long, outer parts curved upwards, branched several times, basal cells 15–25 µm in diameter and L/D 1.5–2, tapering to terminal cells 7–9 µm in diameter and L/D 1.5–2, often with a hair; pyriform gland cells (Fig. 22B) occur on the whorl-branchlets. Cells uninucleate; rhodoplasts discoid to elongate in smaller cells, ribbon like and orientated lengthwise in axial cells.

Reproduction: Gametophytes dioecious. Procarps (Fig. 22B, C) replacing whorl-branchlets, with a supporting cell bearing a curved 4-celled carpogonial branch (Fig. 22C), and with growth of the branch axis continuing with further procarps. Post-fertilization the auxiliary cell divides and the upper cell produces lateral lobes (Fig. 22D) 150–300 µm across of ovoid carposporangia 25–35 µm in diameter, the carposporophyte (Fig. 22A) being protected by adjacent whorl-branchlets. Spermatangia (Fig. 22E) are cut off from terminal cells of whorl-branchlets, ovoid, 2–3 µm in diameter.

Tetrasporangia (Fig. 22F) occur on lower cells of whorl-branchlets, sessile, subspherical, 30–70 µm in diameter, tetrahedrally divided.

Type from King George Sound, W. Aust. (Harvey); lectotype in Herb. Harvey, TCD (Alg. Aust. Exsicc. 485, isolectotype in AD, A18290).

Selected specimens: Topgallant I., S. Aust., 20–25 m deep (Shepherd, 8.xi.1980; AD, A51878). Off Redcliff Point, N Spencer Gulf, S. Aust., on Posidonia sinuosa, 7 m deep (Johnson, 10.ix.1975; AD, A54949). Port Broughton, S. Aust., just sublittoral ( Womersley, 1.xii.1963; AD, A27037 - "Marine Algae of southern Australia" No. 98a). 5 km outside Tapley Shoal, S. Aust., 15 m deep (Shepherd, 2.xi.1969; AD, A33502). Aldinga, S. Aust., on Posidonia australis, 2 m deep (Johnson, 13.ii.1973; AD, A43982). D'Estrees Bay, Kangaroo I., S. Aust., drift (Womersley, 23.viii.1963; AD, A26795). American R. inlet, Kangaroo I., S. Aust., drift (Wollaston, 25.viii.1963; AD, A27059 and on Posidonia, 2–3 m deep near Muston (Kraft, 7.iv.1972; AD, A42409). Saunders Beach, Eastern Cove, Kangaroo I., S. Aust., on Posidonia, drift (Womersley, 25.viii.1963; AD, A26698 - "Marine Algae of southern Australia" No. 98b).

Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: Shark Bay, W. Aust. (Kendrick et al. 1988), to Walkerville, Victoria.

Taxonomic notes: P. australis is the most slender species of Ptilocladia in southern Australia, distinguished by the discrete, separated, whorls with the axial cells clear between the whorls. It is commonest as an epiphyte on Posidonia and some algae in sheltered waters.


AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1- Epicrisis systematic Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)

DE TONI, G.B. (1903). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 3, pp. 775–1521 + 1523–1525. (Padua.)

GUILER, E.R. (1952). The marine algae of Tasmania. Checklist with localities. Pap. Proc. R. Soc. Tasmania 86, 71–106.

HARVEY, W.H. (1855a). Some account of the marine botany of the colony of Western Australia. Trans. R. Jr. Acad. 22, 525–566.

HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. III. Flora Tasmaniae. Vol. II, pp. 282–343, Plates 185–196. (Reeve: London.)

HUISMAN, J.M., KENDRICK, G.A., WALKER, D.I. & COUTÉ, A. (1990). The Marine Algae of Shark Bay, Western Australia. Research in Shark Bay. Report of the France-Australe Bicentenary Expedition Committee, pp. 89–100.

KENDRICK, G.A., WALKER, D.I. & McCOMB, A.J. (1988). Changes in the distribution of macro-algal epiphytes on stems of the seagrass Amphibolis antarctica along a salinity gradient in Shark Bay, Western Australia. Phycologia 27, 201–208.

KENDRICK, G.A., HUISMAN, J.M. & WALKER, D.I. (1990). Benthic macroalgae of Shark Bay, Western Australia. Bot. Mar 33, 47–54.

LUCAS, A.H.S. (1909). Revised list of the Fucoideae and Florideae of Australia. Proc. Linn. Soc. N.S.W. 34, 9–60.

LUCAS, A.H.S. (1929a). The marine algae of Tasmania. Pap. Proc. R. Soc. Tasm. 1928, 6–27.

MAY, V. (1965). A census and key to the species of Rhodophyceae (red algae) recorded from Australia. Contr. N.S.W. natn. Herb. 3, 349–429.

SILVA, P.C., BASSON, P.W. & MOE, R.L. (1996). Catalogue of the Benthic Marine Algae of the Indian Ocean. (University of California Press: Berkeley, Los Angeles & London.)

SONDER, O.W. (1881). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

WILSON, J.B. (1892). Catalogue of algae collected at or near Port Phillip Heads and Western Port. Proc. R. Soc. Vict. 4, 157–190.

WOLLASTON, E.M. (1968).Morphology and taxonomy of southern Australian genera of Crouanieae Schmitz (Ceramiaceae, Rhodophyta). Aust. J. Bot. 16, 217–417.

WOMERSLEY, H.B.S. (1950). The marine algae of Kangaroo Island. III. List of Species 1. Trans. R. Soc. S. Aust. 73, 137–197.

The Marine Benthic Flora of Southern Australia Part IIIC complete list of references.

Author: E.M. Wollaston & H.B.S. Womersley

Publication: Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
©State Herbarium of South Australia, Government of South Australia

Illustrations in Womersley Part IIIA, 1998: FIGS 20A, 22 A–F.

Figure 20 image

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Fig. 20. A. Ptilocladia australis (AD, A33502) Habit. B–F. Ptilocladia gracilis (B, F, AD, A41083; C–E, AD, A39208). B. Habit. C. Young and mid branches with tetrasporangia. D. Branch with tetrasporangia. E. Older corticated branch. F. Lateral branches with carposporophytes in apices surrounded by whorl-branchlets.

Figure 22 image

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Fig. 22. A–F. Ptilocladia australis (A–D, F, AD, A33502; E, AD, A42409). A. Thallus with whorl-branchlets and carposporophytes. B. Branch apex with two gland cells and a procarp. C. A 4-celled carpogonial branch on a supporting cell. D. A young carposporophyte with 2 immature gonimolobes. E. Branchlet with terminal spermatangia. F. Base of a whorl-branchlet with mature and juvenile tetrasporangia. (A–D, E, as in Wollaston 1968, courtesy of Aust. J. Bot.)

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